The simplest and most practical method (which is also commonly used by painters) is to gently lick the paper with the tip of the tongue. If the water seeps quickly and the water marks spread outward, it is a publicity. If water does not seep into the paper, it is cooked. If the water only seeps into the paper, but it doesn't spread out, or it only spreads out in a small amount at a slow speed, it is half-cooked rice paper.
of course, if conditions permit, it is best to try it with a brush dipped in water or ink.